To make a finished photograph from a negative, the image on the negative is printed on light-sensitive photographic paper and the exposed paper is processed. To accomplish this, light is passed through the negative and lenses and onto the printing material. The printing paper is coated with a light-sensitive emulsion containing crystals of silver atoms combined with bromine or chlorine atoms or both. With conventional processing procedures, the printing paper is placed in a developer for several minutes so that chemical action can convert the crystals that have been exposed to the light into metallic silver. The printing paper is next typically transferred to a chemical solution called a stop bath to halt the action of the developer, then is put in a fixer, which removes undeveloped and unexposed crystals, and finally it is washed and dried. This results in a permanent, positive image, the dark areas of the permanent image corresponding to the light areas of the negative, which were generated by the dark areas of the original scene.
Photographic printers and processors are utilized by photofinishers, laboratories, one-hour studios, and other companies in the photography industry. Automatic printers typically include supply and take up rollers for the photosensitive photographic material and a mechanism to automatically advance the material through an exposure area or station. The image to be exposed is established in known manner and projected on the photographic printing paper in the exposure area, with a shutter being employed to control the exposure.
However, conventional printers typically require that the roll of photographic printing material be loaded and unloaded from the printer under darkroom conditions. An operator is needed to manually transfer the exposed sheets or paper roll to the processor, which is often located in a separate room. In addition, the user must often allow an entire roll of paper to be exposed before the paper can be removed to the processor. These procedures are time-consuming and inefficient, resulting in slower photofinishing productivity. Although transport systems which transfer paper from the printer to the processor have been utilized, these devices typically accommodate only a limited number of sheets of exposed printing paper, and they provide limited means to automatically accumulate the printing paper if the processor is in operation.
Another difficulty with conventional printers is that they are sometimes designed to accommodate only a single lens so that the possible print sizes are limited. In printers which enable multiple lenses to be used, changing lenses can be a complicated process. The arrangement for holding the various lenses, such as a lens drawer system, can be quite complex and heavy and may require manual operation. Most conventional printers and processors also accommodate only a single size roll of paper, with only a single paper plane. This also limits the size of photographs which can be produced.
During exposure of the image upon the printing paper, it is important to maintain the printing paper flat and straight against the paper plane in order to produce a clear and properly positioned image. However, automatic advance of the paper across the paper plane sometimes hinders this. One conventional solution has been a paper plane or platen having a series of isolated perforations through which a vacuum is applied. But the number of air leaks decreases as more paper covers the platen, resulting in increased pressure on the paper. This effect results in a non-uniform vacuum, and places a substantial burden on the paper advance drive means.
The present invention addresses these and many other problems associated with currently available methods and apparatus relating to photographic printer-processors.